Switch matrix ... diodes. I learned this problem the hard way in wiring up a MAME cabinet, at about 3 A.M. the night before we were going to bring it to Shmoocon. We finally got the whole USB ...

But the grid controller is less clear. Maybe external I/O expanders or a even bigger matrix? Does it still need diodes at each button? To help answer these questions the folks at [openmusiclabs ...

Figure 4: Luminance of a stretchable display. By integrating a driving-cell active matrix and organic LEDs using printed elastic conductors, we manufactured a 16×16-pixel stretchable active ...